fix(CourseDetailPage): 修复课程详情页日程展开按钮图标方向错误

修复了日程展开按钮图标方向错误的问题，确保图标在展开和收起时显示正确的方向

@@ -84,7 +84,7 @@
                 </div>
                 <div v-if="course?.schedule?.length > 4" class="flex justify-center mt-4">
                   <button @click="toggleSchedule" class="p-2 rounded-full hover:bg-green-50 text-green-600 hover:text-green-700 transition-all duration-300">
-                    <van-icon :name="isScheduleExpanded ? 'arrow-down' : 'arrow-up'" class="text-xl transform transition-transform duration-300" />
+                    <van-icon :name="isScheduleExpanded ? 'arrow-up' : 'arrow-down'" class="text-xl transform transition-transform duration-300" />
                   </button>
                 </div>
               </div>